Pull the hub, pop off the back seal and remove front and back bearings. Clean out the hub really well. Best way to do this is go to the car wash, spay the inside down with some degreaser, and pressure wash them babies out. Dry them off and look at the erasers inside ( if you don"t know what that is it would be the shinny concaved surface in your hub. These things should be perfectly smooth. If there is any scaring then you need to change them also. If you have any trouble let me know and I will walk you through the steps. It's a little time consuming but it's well worth the piece of mind. If you have grease on the back of your rim, your rear seals are bad and chances are your bearings are not far behind.